Latex foam in bedding such as mattresses has been used and is desirable because latex foam is durable and provides a high level of comfort and support. Some foams use latex foam rubber throughout the mattress. These designs are comfortable and durable, however, they are expensive.
Other materials and manufacturing techniques are also employed to improve the comfort and durability of beddings such as mattresses. For example, U.S. Pat. No. 3,320,339 to Smith discloses a mattress formed of a core of relatively low-density latex material surrounded by an integrally-molded border of higher-density latex. To manufacture this mattress, the two materials are poured into two areas of a mold (a center area and the surrounding border), which are separated by a barrier strip. During the vulcanization process, the barrier strip dissolves, and the core and border fuse together. This is an effective design however with this method, the core and border must be formed simultaneously, which may not always be desirable when, for example, the different sections would be optimally vulcanized at different temperatures and/or for different lengths of time. Also, because the mattress is composed entirely of latex foam rubber, it is relatively expensive
For getting a more comfortable structure, these mattresses hold in addition a lot of material layers such as layers made of latex foam, polyurethane foam and all these parts are covered with wool, cotton, or other stuffings and then they are closed in a fabric envelope or sack. The connection of foam layers is obtained using a mechanical process, such as application of metallic stitches or by glueing; these operations are expensive as they require a rather long and tedious manual work and that must be made mainly by skilled workers. The glueing operation can also reduce the mattress duration as, during the use, the glue tends to loose its adhesive capacity; further, the manual glueing operation can be made in incorrect manner or the glue cannot be applied in uniform way on the pieces belonging to the same production lot or also to the same piece.
Further, mattress deformation can be caused also by lying layers, that is to say the superior and lower rest layer, during its use, tend to slide as plates onto the spring structure, as they are joined with another only by the perimetrical layers of molded material that surrounds the envelope, these layers having a reduced mass and therefore are insufficient to lock in stable position the rest layers. In this manner the mattress, both owing to deformations and wear, is no more efficient and comfortable and can be used only for a limited time period (‘stability’).
Toppers for use in bedding or seating products are known. These toppers extend across the entire width and length of the particular bedding or seating product. If the particular bedding or seating product is a mattress, typically one such topper is placed on one side of the mattress core, and a second topper is placed on the opposite side of the mattress core, thereby effectively “sandwiching” the mattress core. This combination then typically is covered with an upholstered fabric covering.
Toppers have been designed so as to provide multiple degrees of stiffness or firmness. In particular, in a bedding structure, which includes an innerspring mattress and a topper, the topper includes a sheet of a foam which is glued. While the glue results in added thickness to the topping. This additional thickness provides a stiffness which may prove uncomfortable to a user and which does not adapt itself to the supporting structure for the topper or mattress (‘adaptability’).
In addition, the glue hinders the quilting operation.
Accordingly, there remains a need for foam, which is relatively easy and inexpensive to manufacture, and which does not need to be formed simultaneously and which need not be comprised of the same material, said bedding addressing the above mentioned drawbacks.
The above-mentioned drawbacks and limitations have been overcome by composite foam for use in a bedding or seating product, in which the bedding has a first layer, which includes latex, and a second layer, which is a foam selected from polyolefin, polyurethane, polystyrene or polyester or mixtures thereof.
With the selected application of latex to said foam, single composite foam may be achieved without the need for the foam being glued or otherwise attached to one another while maintaining a high level of comfort, durability, adaptability stability and quiltability.
It is a further object of the invention to provide a thin composite mattress of the type to be used as a topper for a conventional mattress. More specifically, it is an object of the invention to provide a topper on the order of 0.1 to 10 cm thick that has the area of a conventional mattress. This topper mattress is placed over a conventional mattress and is used to provide the comfort of latex foam without the expensive of replacing the conventional mattress providing the benefits as stated hereinabove.
The topper of the present invention is for use on top of an existing conventional mattress, to increase the comfort of the mattress while utilizing an existing conventional mattress. The topper can be used as an after market product and placed on top of a mattress. Alternatively, the topper can be placed on an unfinished mattress (either a conventional mattress including steel springs or a foam mattress) and the topper and the mattress is then covered with fabric.
These and other preferred aspects of the invention are described in more detail below and will be better appreciated from the detailed description including the FIGS. 1-12.
According to another embodiment of the present invention, the invention is directed to a continuous method of making composite foam including the step of: applying latex to foam selected from polyolefin, polyurethane, polystyrene or polyester or visco-elastic latex or mixtures thereof; curing the latex, thereby forming the composite foam of the present invention.